Dynamically assisted Schwinger pair production in differently polarized electric fields with the frequency chirping

Abstract

We investigate the enhanced dynamically assisted electron-positron pair production in differently polarized electric fields with frequency chirps within the real-time Dirac-Heisenberg-Wigner formalism. The combined influence of the chirp parameter and the field polarization on the momentum distribution and the total number density of the created pairs is studied in detail for one-color field as well as dynamically assisted two-color combined fields. The frequency chirps lead to strong interference effects and significantly enhanced the peak values in the momentum distribution for both one-color field and two-color combined fields. In the dynamically assisted case, the number density can be enhanced significantly over 2-3 orders when large frequency chirp is applied to both strong and weak fields. Furthermore, we observe that sensitivity of the number density to field polarization progressively diminishes as the chirp parameter increases, a trend that holds for both one-color field and the assisted two-color combined fields. These results provide a valuable foundation for the optimal control of pair production, offering guidance for maximizing particle yield within a constrained set of field parameters.

Figures (16)

• Figure 1: Electric field configuration described by Eq. \ref{['eq:field_model']}. The top panels (a) and (b) show the time-series of the field components $E_x(t)$ and $E_y(t)$ for different polarization in chirp-free case ($b_1[\omega_1/\tau] = b_2[\omega_2/\tau] = 0$), while the bottom panels (c) and (d) present the corresponding polar diagrams of the field $\mathbf{E}(t)$. The field parameters are same as given in Eq. \ref{['eq:parameters']}.
• Figure 2: Same as Fig. \ref{['fig:field_chirp_free']} except for $b_1[\omega_1/\tau] = b_2[\omega_2/\tau] = 0.5$.
• Figure 3: Momentum distribution of the created $e^+e^-$ pairs with $k_z = 0$ in the one-color strong field $\mathbf{E}_{1s}$. The plot shows the variation with $\delta$ in a chirp free case $(b_1 = 0)$. The other field parameters are same as Eq. \ref{['eq:parameters']}.
• Figure 4: Momentum distribution of the created $e^+e^-$ pairs with $k_z = 0$ in the one-color weak field $\mathbf{E}_{2w}$. The plot shows the variation with $\delta$ in a chirp-free case $(b_2 = 0)$. The other field parameters are same as Eq. \ref{['eq:parameters']}
• Figure 5: Momentum distribution of the created $e^+e^-$ pairs with $k_z = 0$ in the two-color combined field $\mathbf{E}(t)$. The plot shows the variation with $\delta$ in chirp-free fields ($b_1 = b_2 = 0$). The other field parameters are same as Eq. \ref{['eq:parameters']}.